There are many instances in which it is necessary to collect samples of liquid for analysis purposes. Samples are taken regularly in accordance with Federal, Provincial or industrial monitoring programs from water treatment plants, waste-water treatment plants, P.O.L. compounds, collection systems, storm drains, manholes, catch basins, streams, rivers, reservoirs, water tables, run-offs, chemical plants and other facilities. Sample taking involves the introduction of a collection jar or other container into the liquid to be sampled and the subsequent removal of the container once a suitable volume of liquid has entered the container. It is important that the collection be made quickly and efficiently and that there be no spillage of liquid from the container as it is removed from the vat, stream, pond, or other main container holding the liquid of interest.
It is also important that the sample collected be an accurate representation of the liquid being sampled. In the past, cross contamination of samples has been a problem. Sterile stainless steel cylinders or glass bottles were connected to a pole and dipped into the sample. The sample volume was poured into collection jars or bottles and sent for analysis. To avoid cross contamination from sample to sample, a new stainless steel sterile cylinder or bottle was needed to collect samples from different locations. This meant that many bottles were required when many samples were to be taken.
Another problem associated with previous practices was the danger of manually dipping by hand into the host volume. Extra workers are required when retrieving samples from confined spaces. For example, if a manhole had to be monitored, it was necessary to use three people and considerable equipment for the set-up and sample taking. The person taking the sample would wear a safety harness while the others would set up safety triangles, gas monitoring equipment and a tripod. The person wearing the safety harness would connect to the tripod and lower himself into the manhole to take the samples. After the samples were taken, he would come up and the others would take down the equipment and move to the next sample point. This is a very costly exercise and can be dangerous for the workers involved.